The subject invention relates generally to automatic network diagnostic systems and more particularly to a system for automatically testing and controlling, from a central site, a plurality of centrally and remotely located data modems.
With the increasing complexity of distributed data processing systems, particularly those utilizing telephone data communication between central and remote site data processing apparatus and their associated data modems, the need for testing and control of the data modems has increased. The complexity of present and proposed systems requires the ability to communicate rapidly with modems at diverse and numerous sites. Modem malfunctions become increasingly critical in that one malfunctioning modem may interrupt transmission by many others in the network. Since even very small amounts of down time can mean big dollar losses in distributed processing systems, the need arises to automatically control modems in a distributed system to minimize time losses. To provide efficient and effective operation, it would be highly desirable to provide the modem with the capability to raise alarm signals to a central controller and perform the network reconfiguration and control functions necessary to respond to various trouble conditions. Both for speed and reliability, it is desirable to have as many of these functions as possible performed automatically by apparatus of the system.